PUB00084

• Year: 2004
• Title: Artificial Recharge of Ground Water in Colorado -- A Statewide Assessment
• CWCB Section: Administration
• Author: Colorado Geological Survey
• Description: This study was a special assignment to the CGS from the DNR Executive Director. The tqask was to assess the underground water storage options potentially available in our state.
• Publications - Doc Type: Tech Report

Artificial Recharge of Ground Water in Colorado
A Statewide Assessment

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. Downstream obligations - AR can provide a source of base flow to a stream to meet
in-state obligations such as maintaining minimum in-stream flow conditions. In a
sense, this is a subset of serving as part of an augmentation plan, however, in this case
the downstream needs include non-traditional uses such as maintaining aquatic
habitat or providing recreational opportunities.

. Obligations of interstate compacts - Colorado is obligated to deliver water to
downstream states under a number of interstate compacts and equitable
apportionment decrees. AR can be utilized for water storage to help manage surface-
water resources so that the required deliveries can be met with minimal impact on
Colorado's water needs.

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Mana2eIMiti2ate Water Quality
Physical, chemical, and biological processes in an aquifer have the potential for modifying water
quality. AR can take advantage of these natural processes, through soil/aquifer treatment
(Figure 111-5), to improve water quality ofthe water supply in the following situations:

. Improvement of surface-water quality - AR can be used when surface water requires
a level oftreatment prior to utilization. Bacterial digestion and physical-chemical
processes (geo-purification) in an aquifer can act as a natural treatment facility.
Surface water may contain high levels of suspended or dissolved solids that must be
removed before the water can be placed to beneficial use. AR mitigation is
accomplished by capturing the runoff for recharge infiltration and geo-purification
through an aquifer. The water is then recovered from the aquifer some distance away
from the active channel through wells or infiltration galleries and put to beneficial
use.

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. Improvement of ground-water quality - AR can be used to improve ground-water
quality. High quality surface water can be recharged to an aquifer where the ambient
ground-water quality is impaired by naturally occurring dissolved solids, producing a
lens of higher quality water. Recovered water is of higher quality than the ambient
ground water.

. Disinfection byproducts (DBP) reduction - Chlorination of water can produce
elevated concentrations ofDBP's (trihalomethane compounds: chloroform,
bromoform, dichlorobromomethane, and dibromochloromethane). Treated drinking
water can be used as the source water for AR. Dilution and geo-purification in the
aquifer will reduce the DBP concentrations in the recovered water.

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Wastewater disposal- In this situation, treated wastewater is allowed to infiltrate as
an alternative to discharging to surface water. This option typically requires less
treatment, therefore less expense for wastewater disposal.

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